Automatic electric machinery



Jan. 19,1926. 1,570,591 W. D. MERCER AUTOMATIC ELECTRIC momma? Filed Nov. 1, 1924 William .2 [Yrcer Patented Jan. 19, 1926.

umrso, STATES PATENT OFFICE.

WILLIAM D. MERCER, 015 DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS. TO KELVINATOR CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

AUTOMATIC ELECTRIC MACHINERY.

Application filed- November 1, 1924. Serial No. 747,201.

To all whom it may concern:

Be it known that I, WILLIAM D. MERCER, a citizen of the United States of America, and-a resident of Detroit, in the county of 5 Wayne and State of Michigan, have invented certain new and useful Improvements in Automatic Electric Machinery, of which the following is a full, clear, and exact description.

This invention relates to electrically operated machinery and particularly to electrically operated pumps. The objects of the invention are the provision of a new and simplified arrangement for tightening the 15 driving belt, taking up the stretching thereof, and increasing the degree of its engagement with the driving pulley: also the provision of a more uniform and less noisy drive; while further objects and advantages of the invention will become apparent as the description proceeds.

In the drawings accompanying and forming a partof this application, Fig. 1 is a front elevation of a specimen embodiment of my invention; Fig. 2 is a bottom plan view of one form of motor base; Fig. 3 is a left hand end elevation of part of the motor base shown in Fig. 1; and Fig. 4 is a perspective view of a modification of I my inventlon as applied to a gas compressor. In the drawings I have shown an electric motor 1 having a driving pulley 2 connected by a belt 3 with a drive wheel 4 p which operates either the compressor 5 or 88 any other suitable mechanism. Inasmuch as small sized electric motors nearly always run at a comparatively high s sad, it is generally necessary to reduce t 's eed considerably to accommodate the mac inery to 0 be driven thereby, and this is accomplished most simply by maln'ng the wheel 4 of comparatively large diameter. This arrangement, however, entails the disadvantage that'when the motor and drive wheel are ll cated close together, in order to save room and reduce the cost of the belting, the belt contacts with only a small arc of the pulley so that its tract1ve effect is rather small, and even this is entirely lost by a compara- I tively small stretching of the belt.

In order to overcome this disadvanta e I locate between the pulley 2 and drive w eel 4 an idler ulley 6 fixedly mounted upon a standard in such wise as to wrap the belt more completely about the smaller pulley; and in combination therewith I mount the motor for sliding movement horizontally away from the drive wheel and place it under tension by means of a suitable spring. In the present embodiment I have shown the motor and driven wheel as mounted upon a suitable base 10. In the present embodiment the motor support comprises a rectangular frame having end members 11 bolted to the base 10 and connected by horizontal rods 12 spaced above parallel to the same. Located above these bars is a flat plate 13 carrying the motor and having depending ears 14 slidable along the bars 12, a spring 15 being "employed to force the motor away from the drive pulley thereby holding the belt under tension.

The bracket 7 is preferably mounted between the motor and drive wheel and its upper part is preferably so arranged as to permit an adjustment of the idler pulley transversely of the belt. In Fig. 1 this is effected by forming the up er end of the bracket with an elongated s 0t 16 along which the spindle 17. of the idler can be moved and clamped. In Fig. 4 I have shown this bracket with a plurality of separate holes so thatthe idler spindle can be inserted into one or the other at need. In the latter case care should be taken that the shortening of the belt caused by shifting the pulley from one hole to the 'next is not greater than can be compensated by the sliding movement of the motor along its base. I do not claim the use of an idler pulley broadly, but the customary mode. of using an idler has been to mount it on the end of a pivoted bar, which bar has then vibrated continuously during the operation of the mechanism. Neither do I claim to have originated the sliding motor base for tightening a-belt, but the combination of the two ideas, the sliding motor to take up the slack,

lus a. fixedly mounted idler to wrap the elt more completely about the smaller pulley especially when the idler is adjustable to restore the motor to the beginning of its travel I claim as my invention. Such a device rnns steadily and nietly without the huntin and vibration of the usual idler.

It W1 be understood that the-advantage of my invention increases in proportion with the increase in ratio between the: diameters of the respective wheels and with the proximity of those wheels to each other, but I do not limit myself in any wise except as specifically recited in my annexed claims.

Having thus described my invention what I claim is: I

1. In a device of the character described, in combination, a substantially horizontal base, a motor mounted thereon, a pulley carried by said motor having its axis perpendicular to the direction of such movement, a driven mechanism comprising a pulley located in the plane of said first pulley, a belt surrounding said pulleys, an idler pulley fixedly mounted relative to said base at a point between saidpulleys and serving to increase the area of contact between said belt and the first mentioned pulley, and yielding means acting continuously upon said motor to move it relative to said base in a direction to tighten said belt.

2. In a device of the character described,

in combination, a base, a. motor, and a driven mechanism carried by said base, pulleys carried by said driven mechanism and motor respectively, the pulley of the driven mechanism being of substantially greater diameter than the motor-pulley, a belt embracing both said pulleys, a rigid bracket carried by said base between said pulleys, an idler pulley fixedly carried by said bracket and engaging said belt and wrapping it more completely around the motor pulley, means whereby said idler pulley may be moved to diiferent positions alon a line transverse to the belt and secured xedly in each position, and means constantly acting ,upon said motor to move it relatively to said base with a yielding pressure in a direction to tighten said belt.

In testimony whereof, I hereunto afiix my signature.

WILLIAM D. MIERCER. 

